This invention relates to apparatus for folding a sealing a form. More particularly, it relates to apparatus, including a curved, one-sided, open buckle chute for folding and sealing a form along a transverse edge.
Self-mailers, that is form sheets on which may be printed address information and message information and which then may be folded and sealed to form a mail piece, are well known. A preferred version of such a form sheet is described further below, and in commonly assigned, co-pending application Ser. No. 356,149, filed May 24, 1989. Another is described in U.S. Pat. No. 3,995,808; to: Kehoe; for: UNIT CONTAINING VARIABLE MESSAGES; issued: Dec. 7, 1976. As may be seen by examination of each of these form sheets, in order to achieve complete sealing, it is necessary to apply an adhesive fluid, e.g. water to moisten a remoistenable glue, along a transverse edge of the form sheet.
In commonly assigned, co-pending application Ser. No. 115,220; filed: Oct. 30, 1987 an apparatus for folding and sealing a form sheet is shown. In this apparatus, a straight, two-sided, closed buckle chute is shown in combination with a moistening apparatus. The moistening apparatus includes a plurality of units each of which has a pivotable hammer for pressing a form sheet against a moistened wick as the form sheet is withdrawn from the buckle chute.
It should be noted that because of the closed nature of the buckle chutes, the mechanically complex pivotable hammer arrangement is necessary to manipulate the form sheet within the buckle chute to assure adequate moistening. It should also be noted that the disclosed apparatus is not capable of moistening the form sheet along the transversed edge, but instead, provides a plurality of units for moistening a plurality of spots near the transverse edge but, which do not provide a continuous seal along the transverse edge; and that frictional forces created as the hammers force the form sheet against the wicks create tension in the form sheet, which may cause pre-formed tear lines to prematurely separate.
Another apparatus for folding and sealing sheets is disclosed in U.S. Pat. No. 4,701,233; to: Beck et al.; for: METHOD FOR FOLDING AND SEALING SHEETS; issued: Oct. 20, 1987, which discloses an apparatus for use with a facsimile system to assure privacy of a received facsimile document. The facsimile document is output to a folder sealer system which folds the document so that only an address portion is visible and seals the document by injection of glue dots along the lateral edges.
Accordingly, it is an object of the subject invention to provide an apparatus for folding and sealing a form sheet along a transverse edge which is both mechanically simple and efficient.
It is another object of the subject invention to provide such an apparatus which minimizes the increase in the tension forces in the form sheet as the apparatus is moistened so as to minimize the stress on any pre-formed tear lines which may be provided in the form sheet.